Retreading mold



Sept. 16, 1941.

E. A. GLYNN .2,255,770

RETREADING MOLD Filed March ll,

4INVENTOR n E.A.Gynn

BY l

ATTORNEYS Sept. 16, 1941.

E. A. GLYNN RETREADING MOLD Filed March ll, 1940 5 Sheets-Sheet 2 @uut ATTORNEYS Sept. 16, 1941. E A, @LYNN RETREADING MOLD `Filed March 11,

INVENTOR BM ATTORNEYS Patented Sept. 16, H941 UNITED STATES RETREADING MOLD Edwin A. Glynn, Lodi, Calif., assigner to Super Mold Corporation of California, Lodi, Calif.

Application March 11, 1940, Serial No. 323,328

11 Claims.

This invention relates to a tire retreading mold of the full circle type such as now universally used for retreading purposes, the present mold representing improvements over the well known hinged body-section type of mold, and also over the separated body-section type of mold such as that shown in my Patent No. 2,147,339 dated February 14, 1939.

From long experience with both the above types of mold, I have found that while the angled separating or opening action ofthe body sections of the hinged type of mold is highly desirable to effect initial loosening ofthe retreadedltire from the matrix, the corresponding angular closing movement of the body sections tends to pinch the tire or interfere with the proper centralized positioning of the same in mold.

On the other hand, the parallel closing movement of the body sections of the other type of mold avoids the above named objectionable feature of the hinged mold, but the corresponding parallel separating movement of the body sections tends to mutilate the newly formed tread design on the retreaded tire and it has been necessary to resort to a means to initially angle one body section relative to the other, as for instance is shown in my Patent No. 2,184,119 dated December 19, 1939.

It is therefore the principal object of the presoperation; the fully opened position of the sections being shown in dotted lines.

' Referring now more particularly to the charactersof reference on the drawings, themold comprises upper and lower body sections I and 2 of endless ring-like form and provided with steam chambers 3, to which the'necessaryl steam circulating pipes (not shown) are connected as usual. The section l is stationary and is preferably disposed on a downward slope for better drainage and also .to increase working space thereunder at its high side without unduly elevating the mold as a whole. The section I is rigidly supported from a base 4 by uprights 5, one upright 5 being at the lowest point of said section and two other uprights 6 being at points substantially 90 from said upright 5, thus leaving the space underthe section at its high or front side unobstructed for substantially the diameter of said section. The upright 5 is spaced back from the mold section and is connected thereto by rigid arms 1 disposed on opposite sides of the corresponding diametral line of the section.

The lower body section 2 is connected to the section I at the lowest point on the latter and ent invention to provide a mold which combines between arms 1 for combined angular and paralthe advantages of both previous types of mold "as above outlined, while avoiding their objectionable features. In other Words, the mold sections close with a final parallel movement, and initially open with an angular movement.

A further object is to provide a mold in which placing of a tire into position in the mold is facilitated, without the aid of lifting devices.

lA further object of the invention is to produce lel movement relative to section I by a hinge pin comprising upper and lower portions 8 and 9 pivoted together at adjacent ends, the upper portion being rigid with section I while the lower portion 9 is slidable in a boss I0 formed on section 2 with its axis parallel to that of said section. y

Matching matrix sections II to engage a tire T, are mounted in the body sections, and are overlapped along their sides by skirts I2 projecta simple and inexpensive device and yet one ing from and integral with the steam chambered which will be exceedingly eiective for the purposefor which it is designed.

These objects I accomplish by means of such structure and relative arrangement of parts as willfully appear by a perusal of the following specification and claims.

In the drawings similar characters of reference indicate corresponding parts inthe several views:

portions of said sections, and ribbed as at R for strength.

The lower body section 2 is opened and closed means Z Extending between the lower section 2 at the front and the base 4 below is a toggle link unit I3, broken slightly toward the back from a dead center position when the mold is fully closed as Figure 1 is a Sectional elevation of the mold 50 shown in Fig. 3. The piston rod I4 of ahydraulic showing the position of the mold sections at the inception of their relatively parallel movement during a mold closing operation.

Figure 2 isa fragmentary top plan View of the upper mold section.

or rair cylinder I5 is connected to the link unit, the cylinder being pivoted in connection with the base 4 adjacent the back of the mold. y

Another toggle link unit I6 extends between the basel 4 behind the cylinder just ahead of upright 5, andthe boss lu behind pin e, the links of this unit being the same length as those of unit I3. This link unit is also broken slightly in a backward direction from a dead center posi` tion when the 'mold sections are fully closed, andv can only Vbreak a limited amount in the same direction due to the obstruction oieredby vupright 5. the upper links of units I3 and Ilthis p ull unit comprising a rod I1 yconnected to link unit I6, a yoke I8 connected to 'unit I 3` and throughthe base of which the rod slidably projects and a A collapsible pull unit extends between 2,255,770 o Y l, Y

of course applied to the fronttoggle unit, pulling the mold section 2 at the front down from the upper section 2, and thus positively disengaging the adjacent portion of the'tire from the matrix. Since there is nothing to denitely break the rear toggle link unit and the'tire tends to remain rmly engaged with the adjacent portion of the matrix, the rearend of the lower section will be temporarilyeheld from dropping and said section 'swings about the hinge pin as an axis, giving the "desired rinitial angular opening ofthe mold. This holding of the back end of section 2 f against dropping is aided by the fact that since head or nut I9 on the rod to engage the yoke and1 limit relative axial or extending movementvof ,they

rod and yoke without preventingL contracting movement thereof.

`The pull unit is arranged relative tothe toggle'-f' units so that when the latter are adjacent saidjV dead center positions, or in other corresponding parallel relationship, the rod and yoke of the" pull unit are fully extended relative to each other. A locating orcentralizing pin 2(0p'aralle1 to the axis of the uppermolitl.` section I, is 'slidabl'yv mounted in the latter` at the front for axial movement; the lower moldisection 2` havingla shallow socket 2I to receive'the .,lowerend of ythe locating pin, which is pointed."v By making the pin slidable it may project a sufficient distance below sec-V tion I to engage the socket inthe Alower-.section while the latter'isstillfsome rcriistfanceJ from .a closed position. and so insuringproper centralizing of the'mold sections r f rom thenA oni y inaklvlgfthe socket.shallow, the pin cannotenternfar enough 4to' bind vrwith' fthel subsequent angular opening ,movement of theesectifons; the pinof course Ysliding up as themold .sections move to a closed position.v

In operation, Iand'assuming at tnefstart that the lower mold-section is droppedlto its limit for the insertion ofY a tire,it 'will be seen, as indicated byfthe dotted lineposition irfFig.` 4, ythat the front 1mi: unit |73 is. Wen Vbmkenor folded, trie i 1 piston rodA I4 is fully retracted inthe cylinder,

and the back linkunitfll is VVbroken back to the limit allowed by Vupright 5while `the pull unit Ile-.I8 is relativelycontracted and the adjacent end of section. 2 is .lowered on`fpin 4il. `vIi-will also be seen that the lower mold section is disposed vwith a downward slope Atol the frontjifacilitating 3 thek placing of a tire from the Hoor intosaid section-f Y -q i- When the pressure is applied to the cylinder I5 to advance rod IlLthefrontl tdggleflink'unitfIB i becomes fstraightenedv,lraising the frontendnof the. lower mold. section'f2-Y VThe back link unit I6,

remains'.- inits broken position, vsince there is yet l noY force applied torstraighten the' Same,- and the weightA of the mold tends to hold it broken. As a result, the .mold section 2'l closes with an angular motion', turningY on the hingepinras an`axis.`

As the section-2V approaches a `closed position j theY back link unit I6 is connected to boss I0 behind the hinge pin, the said link unit is pulled up to `an evenstraighter or more nearly dead center position than before, thus olsetting any tendency Y for the back end of the mold section to drop.

VThis will be apparent from a comparison of the Y -link unit relative to its dead center line as indicated in Figs, 3 and 4. As soon as-the lower sec- Vtionf22has vthus'angularly dropped sulicientl to disengage, theback end ofthe tire from the matrix, or `at least seriously weaken the holding lplacing said unit in the position it assumes until the subsequent closing operation is carried out to i Vand the mold sections are parallel to eachother, i, which. is just before the. tireactually enters the 1 up'puerY matrix'rn'mber 3, the pull'unit reaches a l fully extended position shown in Fig. 1. A furtherVVV straightening of llink unit I3 tliere-VV foro .also straightns link unit I 6, and since the links of .the units aref the'samelength,1the.sec

1 tion 2 will .be moved up toa closed position `while remaining parallel to lthe upper section. VWhen` the mold is vthus fully closed, the sectionsV are held closed'independentlyof Vthe power cylinder by 1 any suitable meanssuchasis commonly! used fory the purpose.,Y` 'f u f ,Uponop'ening the mold, :the opening pull is onlyA again straighten the unit. j fFro'm the Yforegoing'description it will be readilyV 'seen 'that I have produced such a device as substantially 'fulfills'the objectsof the invention as s'et'fo'rth herein.k y While 'this specication sets forth in detail the present'and preferred construction ofthe device, still in practice such deviations from sucl'ifdetail may be resorted to asfdo not form a departure from the spirit ofthe invention, as dened by the appended claims. f Having thus described my invention, what I claini new and' useful'and `desire to secure by Letters Patent is: Y 1. A tire mold including a pair of separate full-circle vcooperating body sections ltogether adapted toleceive a'tire, means mounting one section, against'movemend means hinging the sections together at one side for relative angular opening and closing movement, and including a member slidably projecting through'the other section and parallel'to the axis thereof, a togglelink lunit connected: to the otherj section and positioned opposite the hinge means and are ranged when approaching a dead center .posi

tionto dispose the'side of the sections opposite the hinge means in closed relation to each other, means 'connected' to said unit *tocollapse.Y and extend the sameV instrumentalities connecting the unit and saidothersection at the vhinged sidejthereof and `including yieldable means clisposed to cause limited separating movementofv closedp'osition in response to a further extending movement of the unit while maintaining such parallel'relationship;withjthe one section. Y

y 2.A ltire mold including a lpair of separate full-circle cooperating` body 'sections together adapted to receive a tire, means mounting one section against movement, meansl hinging the sections together at one side for relative angular opening and closing movement, and including a member slidably projecting through the other section and parallel to the axis thereof, a toggle link unit connected to the other section and positioned opposite the hinge means and arranged when approaching a dead center position to dispose the side ofthe sectionsopposite the hinge means in closed relation to each other, means applied tosaid unit to collapse and extend the same, another toggle .link unit connected to said other section and arranged when approaching a dead center position to dispose the sections at the adjacent side in closed relationship and capable of limited collapse4 from such position and means connecting the link units and adapted Vwhen thev other toggle unit is collapsed and after the arrival of the other section at a position parallel to the one section in response to the extending movement ofthe first named toggle unit, to extend the other toggle unit in response to a further extending of the rst named unit and to the same extent.

3. Atire mold comprising a base, upper and lower full-circle cooperating body sectionsto receive a tire disposed above the base, means rigidly supporting the upper section from the base, means hinging the sections together at one side for opening and closing movement, a toggle link unit extending between the base andthe lower section at the side thereof opposite the hinge means, said unit being extended when the sections are closed and means between the unit and base to control the movement of the toggle link unit, said hinge means including a member slidable in the lower body section and parallel to the axis thereof, another toggle link unit between the base and the lower section adjacent said member, said other link unit being extended when the sections are closed at the corresponding side and being arranged for limited collapsing movement with the lowering of the lower section on the member and means connecting the link units to extend the other link unit after the same is collapsed and with the further upward closing movement of the lower section at its opposite side obtained in response to the aocompanying extending movement of the one link unit and after the lower section in its lowered position on the member has arrived at a position parallel to the upper body section.

4. A tire mold comprising a base, upper and lower full-circle cooperating body sections to receive a tire disposed above the base, means rigidly supporting the upper section from the base, means hinging the sections together at one side for opening and closing movement, a toggle link unit extending between the base and the lower section at the side thereof opposite the hinge means, said unit being extended when the sections are closed and means between the unit and base to control the movement of the toggle link unit, said hinge means including a member slidable in the lower body section in a plane parallel to the axis thereof, another toggle link unit between the base and the lower section adjacent said member, said other link unit being extended when the sections are closed at the corresponding side and being arranged for limited collapsing movement in the same direction as the first named unit and with the lowering of the lower section on the member, the links of the units being the same length, and a pull unit contractible from a predetermined length connecting corresponding links of the toggle units, said pull unit being fully extendedwhen said links become parallel with eachother.

v 5. A tire mold comprising a base, upper and lower full-circle cooperating body sectionsA to receive a tire disposedabove the base,.means rigidlysupporting the upper .section from the base, means hinging the sections together vat one side for opening and. closing movement, a toggle link unit extending between the base and the lower section at the side thereof opposite the hinge means, said unit being extended when the sections are closed, means between the unit and base to control the movement of the toggle link unit, said hinge means including a member slidable in the lower body section and parallel to the vaxis thereof and down which said section may slide a predetermined distance and instrumentalities connecting the toggle unit and the lower section adjacent said member adapted to raise said member from a lowered position when the toggle unit is being extended and to raise the lower section at the opposite side when said section has assumed a position parallel to the upper section.

6. In a tire mold, mold body sections mounted together at one side for opening and closing movement, a locating pin mounted in one section at the opposite side for sliding movement in a plane parallel to the axis of said section, and projecting beyond the face of the section nearest the other section, and a relatively shallow socket in said other section to receive the adjacent end of the pin.

7. A tire mold comprising upper and lower mating mold sections, a bas-e below the sections, means rigidly supporting the upper section from the base, a hinge connection between the sections on one side and including a depending member slidable in the lower section, a toggle link unit connecting the base and the lower section adjacent said member and disposed in an extended position when the sections are closed and adapted for limited collapsing movement in a direction away from the opposite side of the sections, another toggle link unit connecting the base and the lower section at the side opposite the hinge means, said other unit being disposed in an extended position when the sections are closed and adapted for collapsing movement in the same direction as the first named unit, means connected to said other unit to extend and collapse the same, and a pull unit connecting corresponding links of the toggle link units; said pull unit comprising a rod connected to a link of one toggle unit,ayoke connected to a link of the other toggle unit and in which the rod is slidable, and a yoke engaging stop on the rod to limit relative sliding of the rod and yoke in an extendingl direction, said pull unit being in a fully extended position when the mold sections are closed.

8. A tire mold comprising upper and lower mating mold sections, a base below the sections, means rigidly supporting the upper section from the base, a hinge connection between the sections on one side and including a depending member slidable in the lower section, a toggle link unit connecting the base and the lower section adjacent said member and disposed in an extended position when the sections are closed and adapted for limited collapsing movement in a direction away from the opposite side of the sections, another toggle link unit connecting the base and the lower section at the side opposite the hinge means, said other unit being disposed in an extended position when the sections are closed and rection as the rst named unit means connected to said other unit'to extend and collapse. the

' same,land.a collapsible. pull unit connecting the 4 toggle link units and'frullyvextendedwhen the link units are adjacent'dead centerpositionsandthe mold sectionsare closed. Y jY 9. A mold as in vclaim 8, in which theA first named toggle; link unit is disposed to .one side of a dead center position in the direction of collapse when the mold sections are closedand the pull unit is extended, whereby when the tension on the pull unit is relieved in response to a collapsing movement of` the other toggle llink zunit, the rstv named toggle link unit will be moved toward a collapsed position by the weight of the lower kmold section; Y

109A tire mold comprising Vupper and lower mating mold sections ,*abase below the sections, means rigidly supporting the -upper section from the base,ja hinge connection between the sections on one side and including a depending member slidable inthe lower section, aA toggle link unit connecting the base and the lowersection adjacent said member and disposed'in an extended position Vwhen the sections are Vclosed and adapted for limited collapsing movement in one direction, another toggle unit connecting the base and the lower section at the opposite side thereof, said other unit being extended when the mold sections are closed and adapted for collapse in one direction, means connected to said other Vlnk--unitto collapse and extend the same, and

a collapsiblepull unit connecting the toggle link untst'oplill the rst named link unit to an extended position .after the same has been collapsed in response. tofan extended movement of the other link unit while allowing said other link linit to collapser .to .a greater extent than the firstrnamed link unit.

, ,11. A tirev moldcomprising mating mold sections, a base, Ymeans rigidly supporting one sec- -tion from the base, a hinge connection between the sections on one side and including a member slidable inthe other section, a toggle link unit connectingthe base and said other section adjacent said member and Vdisposed in an extended position when the sections are closed and adapted Afor limited collapsing movement in one direction, another toggle link unit connecting the base and said other section at the` opposite side thereof, said other link unitjfbeing extended when the sectionsare closed and adapted for collapse in one direction, means between thevbase and said other link unit uto collapse and extend the same, and a collapsible pull vunit connecting the toggle linkV runvits'to, pull the first named link unit to an extended position after the same has been collapsed inresponse to an extending movement of the other link unit while `allowing .said other link unit to collapse agreater extent than the iirst namedlink unit.A l Y EDWIN A. GLYNN. 

